The present invention relates in general to a label product and in particular to an improved label product that minimizes cold flow of adhesive along label edges.
Some pressure sensitive adhesives used in the manufacture of forms and labels are known to cold flow, or ooze, when exposed to combinations of elevated ambient temperatures and pressures. Essentially, the adhesive creeps out from under the cut edges of the label resulting in exposed adhesive that can leave deposits, clog machinery, and cause items to stick to the exuded adhesive. Conditions that lead to adhesive oozing can be encountered in both the storage of forms as well as the processing of forms.
Where forms are stacked in either cut sheet, or in folded or rolled form, the pressure of the layers can sometimes cause adhesive ooze. Likewise, when processing forms, ooze may cause the contamination of printers and other machinery. For example, laser printers are susceptible to adhesive ooze due to the heat and pressure internal to the printer. Labels may stick to components inside the printer, or in stacking trays or feeding trays.
One known label construction that attempts to avoid the problem of adhesive ooze is to apply pressure sensitive adhesive in a pattern that extends along the back surface of the label ply, but stops short of the label edge, thus the periphery of the label is adhesive free. While this approach may reduce adhesive ooze, the adhesive free edges can become prone to lifting, folding over, or otherwise obstructing machinery, and can further affect stacking of forms in feed and output trays. Another label construction involves pattern coating an adhesive to create a gap beneath the label free of adhesive. This may lead to adhesive migrating to the adhesive free region under the label instead of migrating beyond the periphery of the label. However, there is nothing that positively prevents adhesive from migrating from the outer periphery of the label. While some adhesive may fill the gap, depending upon gap placement, other adhesive may still creep out from the outer periphery. Further, the back surface of the label is not full coated with adhesive, which may compromise the strength and utility of the label. In addition, most pattern adhesive labels are a custom manufactured product resulting in higher cost of production.
Yet another solution involves applying a pattern coating of silicone to the liner ply. The liner ply is silicone free about the periphery of the label. A die cut contours the periphery of the label, set inward a predetermined amount. The adhesive bonds the back of the label ply to the silicone free portion of the liner ply, about the periphery, avoiding the migration of adhesive ooze outside the periphery of the label. However, this label construction can be difficult to practice. The labels may rip or tear where the edges of the label are adhered to the liner in a silicone free area. Further, it may be difficult applying the pattern of silicone to the liner ply in the pattern required to contain the ooze.
Accordingly, there is a need for an improved label construction that reduces adhesive ooze.
The present invention overcomes the disadvantages of previously known label constructions that reduce adhesive ooze from exuding from a label edge by providing a label having a barrier coating that forms a stable and resilient film over at least a portion of the label periphery, and overlaps an area adjacent to the label periphery. The barrier coating traps adhesive ooze that may exude from a label edge. The area adjacent to the label periphery may comprise a liner ply, a form ply, or an adjacent label ply.